The propane gas industry has traditionally used two methods for the determination of gas leakage in the piping of a propane system. The first method involves the placement of a high pressure test block in the high pressure section of the propane system immediately upstream of a first stage regulator. Gas is introduced into the system, and a 300 psig (pounds per square inch, gauge) pressure gauge is monitored for a period of ten minutes. If a drop in pressure is noted by the technician, a leak is considered to be present downstream of the test section. If the pressure gauge holds steady, no leak is present.
The second method used by the industry is a low pressure method which employs a water manometer. The manometer is connected to the low pressure section of the delivery system, typically, at a gas range orifice inside of the residence. After the manometer is installed, the technician monitors the water column level for three minutes. If there is a decrease in water column height, gas leakage is determined to be present in the system. This method requires that the technician have access to the inside of the house and that all known gas flows, such as free-standing pilot lights, be shut off.
The above described tests, although accurate for determining the existence of leaks, involve a moderately high level of skill from the technician and are very time consuming. On the average, a typical test requires at least twenty minutes. Productivity suffers to a great extent if a delivery person has several gas outage calls in a single day. Additionally, these tests cannot quantify the leak rate; they can only inform the delivery person that a leak is present.
Propane gas outages call for special attention by the delivery person to ensure that there are no unacceptable and dangerous leakages in the system. In most cases, propane gas outages simply involve the customer running out of gas because of failure to order a gas delivery or through other circumstances that do not relate to gas leakages. However, the propane industry has adopted a standard of care in which a gas leakage test is generally performed after all gas outages. Because the conventional methods of testing for propane gas leaks are complicated and time consuming, a test procedure that allows for quick and precise determination of leakage in a propane gas system following a gas outage is desirable.